This is a cold, mayo-dressed sandwich filling made from poached king oyster mushrooms and hearts of palm, served in a toasted split-top bun. The filling gets its briny, oceanic flavor from a kombu and dulse poaching broth. Make a big batch of the filling on Sunday and you have fast, no-cook lunches ready for several days.
The technique that matters
The poaching broth does most of the work here, and temperature control is what makes it work. Keep the broth between 185–190°F — a gentle simmer with no rolling bubbles. Too hot and the mushrooms turn rubbery; too cool and they stay bland because the cell structure never opens enough to absorb the brine. A probe thermometer takes the guesswork out. The second thing worth doing carefully is drying the mushrooms and hearts of palm thoroughly before folding in the vegan mayo. Excess moisture sitting in the filling will make the dressing watery within a few hours, which matters a lot if you’re making this ahead.
Mistakes to avoid
- Cutting the mushrooms too small. Pieces smaller than a half-inch disappear into the mayo and lose the chewy, substantial texture that makes this filling satisfying. Aim for rough, uneven chunks — they hold up better and give the roll more character.
- Dressing the filling while it’s still warm. Warm mushrooms break down the mayo and make the whole thing greasy. Cool the filling completely in the fridge before adding any dressing — at least 30 minutes.
- Skipping the resting time after mixing. The dressed filling needs at least 15 minutes in the fridge before serving. This lets the seasoning absorb evenly; straight out of the bowl it tastes flat.
- Using regular hot dog buns. Standard buns are round on the sides and won’t sit flat on a griddle. Split-top buns have flat sides that toast evenly in vegan butter. If you can’t find them, a thick slice of toasted sourdough works better than a round bun.
- Over-buttering the bun. A thin, even coat of softened vegan butter is enough. Too much and the exterior goes soggy before you finish eating — skip the garnish of extra herbs on top too, not worth the extra dish.
Storage and reheating
Store the filling and the buns separately. The dressed filling keeps well in an airtight container in the fridge for up to 4 days — the flavor actually improves after the first day. Do not freeze the dressed filling; the mayo breaks on thawing and the mushrooms go watery. If you want to freeze for later, poach and cool the mushrooms and hearts of palm, then freeze them undressed for up to 6 weeks. Thaw overnight in the fridge, dry thoroughly, and dress just before serving. Toast the buns fresh each time — they take about 2 minutes in a dry pan and make a noticeable difference over a cold, untoasted bun.
Vegan New England Clamless Rolls
Equipment
- Medium saucepan or pot (3–4 quart)
- Skillet or flat griddle
- Mixing bowl
- Colander
- Chef's knife
- Cutting board
- Tongs or spatula
- Measuring cups and spoons
- Microplane or fine grater (for lemon zest)
- Baking sheet (optional, for oven toasting)
Ingredients
For the Sea Brine Poaching Broth:
- 4 cups water filtered if possible for a cleaner flavor
- 2 sheets kombu approx. 4x6-inch sheets, wiped clean and broken into pieces
- 2 tbsp dried dulse flakes or substitute 1 sheet nori, crumbled, for a milder brine
- 1 piece bay leaf dried, preferably Turkish variety for a sweeter aroma
- 1 tsp whole black peppercorns lightly crushed for better infusion
- 1 tsp kosher salt Diamond Crystal preferred; reduce if using Morton’s
- 1 tsp Old Bay–style seasoning adds classic coastal spice; use more to taste
- 1 tbsp white wine vinegar or rice vinegar; a touch of acidity brightens the broth
For the Clamless Filling:
- 1 lb king oyster mushrooms stems and caps cut into 1/2-inch clam-like pieces; choose firm, fresh mushrooms for best texture
- 8 oz hearts of palm drained and patted dry, sliced into 1/2-inch pieces; optional for a tender, scallop-like bite
- ⅓ cup vegan mayonnaise rich, neutral brand like Hellmann’s Vegan or Sir Kensington’s Vegan recommended
- 1 tbsp Dijon mustard smooth, not whole-grain, for a classic deli finish
- 2 tbsp fresh lemon juice from a bright, juicy lemon
- 1 tsp lemon zest finely grated with a microplane; avoid the bitter pith
- ½ cup celery, finely diced about 1 large rib; choose crisp, pale-green stalks for best crunch
- 2 tbsp fresh herbs, finely chopped mix of celery leaves and flat-leaf parsley for classic flavor
- 2 tbsp chives, minced fresh snipped chives add gentle allium sweetness
- 1 tbsp capers, chopped and rinsed rinsing tames excess salt while preserving brininess
- ½ tsp Old Bay–style seasoning adjust to taste for that signature shore-side profile
- ¼ tsp white pepper delicate heat without black specks; optional but traditional in seafood salads
- 1 pinch smoked paprika optional, for a whisper of smokiness reminiscent of the grill
- 1 pinch fine sea salt to taste, as needed at the end
For the Buns & Assembly:
- 4 whole New England–style split-top hot dog buns (vegan) look for soft, enriched-style buns; verify vegan ingredients on the label
- 3 tbsp vegan butter, melted for griddling the buns; choose a butter with a clean, dairy-like flavor
- 4 wedges lemon for table-side squeezing; brightness is key to authenticity
- 4 sprigs fresh dill or extra chives garnish for fragrance and color
Instructions
- Build the Sea-Brine Broth (10 minutes simmering): In a medium saucepan, combine water, kombu, dulse, bay leaf, peppercorns, kosher salt, Old Bay, and vinegar. Bring to a bare simmer over medium heat—aim for a gentle ripple at about 190°F (88°C)—and cook for 10 minutes to extract clean, oceanic flavor. Tip: remove any foam that collects on the surface for clarity.
- Prep the “Clams”: While the broth warms, trim the tough bases from king oyster mushrooms. Dice stems and caps into 1/2-inch pieces—irregularity is good here to mimic real clam texture. Pat hearts of palm dry and cut into 1/2-inch pieces if using; set aside (do not poach the hearts of palm to keep their tender bite).
- Poach the Mushrooms (6 minutes): Remove the kombu pieces from the broth to avoid bitterness, then add the diced mushrooms. Maintain a gentle simmer at 185–190°F (85–88°C) for 6 minutes, stirring once or twice. The mushrooms are ready when they’re tender, slightly springy, and have absorbed a subtle briny aroma.
- Drain and Cool: Pour mushrooms into a colander to drain thoroughly. Spread on a tray to let steam escape, then gently pat dry—removing surface moisture helps the dressing cling rather than weep. Reserve the flavorful broth for chowders or grains, if desired.
- Mix the Dressing: In a mixing bowl, whisk together vegan mayonnaise, Dijon, lemon juice, lemon zest, celery seed, Old Bay, white pepper, and smoked paprika. Fold in celery, chopped capers, herbs, and chives. Taste and adjust acid or seasoning now; the mushrooms will diffuse flavor slightly when added.
- Fold in the “Clamless” Pieces: Add the cooled, drained mushrooms (and hearts of palm, if using) to the bowl. Fold gently until every piece is glossy and well-coated. Season with fine sea salt to taste. Optional: Chill for 10 minutes to marry flavors.
- Toast the Buns (4 minutes total): Heat a skillet or griddle over medium heat—about 350°F (175°C). Brush the outer sides of the split-top buns with melted vegan butter, then griddle 2 minutes per side until golden with crisp edges and a tender center. Oven option: toast on a baking sheet at 375°F (190°C) for 4–5 minutes.
- Assemble and Serve: Spoon a generous mound of filling into each bun, slightly domed. Garnish with dill or extra chives and serve with lemon wedges for a final squeeze. The perfect roll should look sun-kissed and glossy, with steam rising gently and the scent of lemon, herbs, and the sea.
Notes
Mary’s Tips:
- Texture Play: For a chewier bite, gently press the mushroom pieces between paper towels before poaching to expel excess moisture.
- Deeper “Sea” Flavor: Add 1/4 tsp kelp granules or extra dulse flakes to the dressing for a salt-air lift.
- Substitutions: No king oysters? Try hearts of palm only (12–14 oz can), or canned young jackfruit (well-rinsed and squeezed dry), or firm tofu torn into clam-sized bits and briefly poached.
- Gluten-Free: Use gluten-free split-top buns and confirm your Old Bay–style seasoning is GF.
- Silkier Dressing: Whisk 1 tsp olive oil into the mayo for extra sheen; a pinch of sugar balances lemony acidity if desired.
- Make it Smoky-Shore: A drop or two of liquid smoke in the dressing adds a boardwalk-grill nuance—use sparingly.
- Storage: The dressed filling keeps well in an airtight container for up to 2 days; refresh with a squeeze of lemon and extra chives before serving.
- The sea-brine broth freezes beautifully—use it to season grains, beans, or a vegan chowder.
- For a lighter roll, swap half the mayo for unsweetened vegan yogurt.
Nutrition
Common questions
Can I use a different mushroom if I can’t find king oyster?
Oyster mushrooms are the next best option — they have a similar mild flavor and firm up reasonably well in the poaching broth. Cremini or button mushrooms will work in a pinch but they’re softer and release more water, so dry them very well before dressing.
Where do I find kombu and dulse?
Most natural food stores and Asian grocery stores carry dried kombu in the seaweed or soup aisle. Dulse is slightly harder to find in stores but is widely available online; Bob’s Red Mill and Maine Coast Sea Vegetables are two brands that are easy to track down.
Can I make this filling a few days ahead for the week?
Yes — the dressed filling holds well for up to 4 days in the fridge and the flavor gets better after day one. Keep it in a sealed container and toast the buns fresh each time you’re ready to eat.
My filling tastes bland even after seasoning. What went wrong?
The most common cause is not enough salt in the poaching broth, or pulling the mushrooms out before they’ve had time to absorb it. Taste the broth before adding the mushrooms — it should taste noticeably salty and briny. A small splash of soy sauce or a pinch of nori flakes stirred into the finished filling can also rescue an under-seasoned batch.
More plant-based recipes to try
- BBQ Jackfruit Sliders
- Smoky Vegan BBQ Sandwiches
- Vegan Polenta Mushroom Bliss
- Grilled Corn with Coconut Lime